The major objectives of this program are to elucidate the biochemical and biological properties of the genetically-distinct collagens elaborated in the connective tissue matrices of vertebrates organisms. These studies involve: 1) extraction of collagens from various tissues; 2) development of selective precipitation and chromatographic techniques allowing the isolation and purification of individual molecular species of collagen; 3) characterization of the molecular species with respect to chain composition and chemical properties of the isolated chains; and 4) the production of specific polyclonal antibodies to various molecular species in order to assess their tissue distribution by immunohistochemistry as well as by immunoelectron microscopy. Utilizing the indicated rationale and approaches, this program has been instrumental in discerning the unique biochemical properties and potential physiological roles for type I, II, III, IV, V and VI collagens. No major shifts in direction or emphasis of the current research effort are contemplated at this time. In this regard, it is the intention of the investigators to address several key remaining issues relevant to the molecular diversity of the collagen family of proteins, with emphasis on studies concerning several of the more recently-described collagens which are generally present in relatively small quantities in various tissues.